package com.shou.util;

import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.util.Arrays;

/**
 * 请求椒盐工具类
 * @author Administrator
 * 
 */
public class SignUtil {
	private static final String token = "terryWeixinExercise";
	
	public static boolean checkSignature(String signature,String timestamp,String nonce){
		String[] arr = new String[]{token,timestamp,nonce};
		Arrays.sort(arr);
		StringBuilder content = new StringBuilder();
		for(int i=0;i<arr.length;i++){
			content.append(arr[i]);
		}
		MessageDigest md = null;
		String tmpStr = null;
		
		try {
			md = MessageDigest.getInstance("SHA-1");
			//将三个参数字符串拼接成一个字符串进行sha1加密
			byte[] digest = md.digest(content.toString().getBytes());
			tmpStr = byteToStr(digest);
		} catch (NoSuchAlgorithmException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		content = null;
		return tmpStr !=null?tmpStr.equals(signature.toUpperCase()):false;
	}
	
	/**
	 * 将字节数组转换为十六进制字符串
	 * @param byteArray
	 * @return
	 */
	private static String byteToStr(byte[] byteArray){
		String strDigest = "";
		for(int i=0;i<byteArray.length;i++){
			strDigest += byteToHexStr(byteArray[i]);
		}
		return strDigest;
	}
	
	/**
	 * 将字节转换为十六进制字符串
	 * @param mByte
	 * @return
	 */
	private static String byteToHexStr(byte mByte) {
		char[] Digit = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 
				'A', 'B', 'C', 'D', 'E', 'F' };
		 char[] tempArr = new char[2];
		 tempArr[0] = Digit[(mByte >>> 4) & 0X0F];
		 tempArr[1] = Digit[mByte & 0X0F];
		
		 String s = new String(tempArr);
		 return s;
	}
}
